Posts tagged with "solar-panel"
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How To Think About Return On Investment
Sometimes we may want to compare two investment opportunities and figure out which is a better one. Say for example should we rent or buy a house? One way go about it is by using the return on investment method. Basically we calculate how much return we might get going with each opportunity and pick the one with better returns. It is usually not as cut and dry especially if we are dealing with different risks. Yet, it is a good practice to at least find the numbers and later decide if the difference in returns is worth the risk. So in this post, I will discuss how I go about calculating the return on investment. You may have other metrics or different way to look at things, so don’t consider this to be the only option.
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Solar System Comparison with MKBHD
Some of you may already know MKBHD, a popular youtuber in the tech world. He recently posted a video about the going completely solar and not having to pay an electricity bill for a whole year. It is a very well made video which explains how the solar panel system works with batteries (off grid) and with net metering (on grid). Although I don’t have net metering and I am not completely off grid, so mine is a hybrid approach. Still, if you watch the video it will help you understand how my setup works (sort of). My setup is closer to the hybrid system explained in another video. Anyway, I wanted to compare my puny setup with MKBHD’s setup and see how I compare. So here goes.
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Power Bill Is Zero, Thanks To Solar Panel
If you remember, I recently posted that I cannot add any more solar panels given my current setup. You might also recall that I have a lone 320 W solar panel. Surely that cannot generate enough power to reduce my electricity bill to zero. Yet, my latest electricity bill is exactly zero. Thats what happens when you mix politics with lifestyle. Some of you might understand what I am talking about. For others, here is the clue – Gruha Jyothi scheme. Unless you like reading about politics, or belong to Karnataka, one of the southern states of India, you might not know what I am talking about. Let me explain.
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Why I Cannot Add More Solar Panels
You might know that we currently have a sole 320W solar panel. Initially I just wanted to check if it was worth buying a solar panel. While there is a lot of talk about the many benefits of solar panels, I was not so sure. Will the panels really last a long time like they claim. Will the efficiency reduce quickly as the panel ages. Will the panels really produce the rated power because they are tested in ideal laboratory conditions of 1000 W/m2 irradiance, but in real life I was not sure if we get so much sunlight etc. Well, after owning the panel for over 2 years now, I can tell you that most of my doubts have been clarified. So I was wondering if I should add another panel.
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How Much Money Did My Solar Panels Save? - 2023 Edition
A long time ago I wrote a post on how much money my solar panel was saving me. In the post I promised to write another post in November 2022 with updates. Well, lots of things happened and I completely forgot about it until one reader reminded me requesting for an update. So here it goes. It has been more than 2 years since I installed a 320W solar panel and I have been diligently collecting data from my panel, our consumption and how much we are pulling from the grid. Very recently I finally finished my code to fetch the data, massage it and used some nice libraries to draw the graphs so I can analyze the data.
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Solar Panel Project Update - Part 5
This is the final update in the solar panel project series for now. Hopefully by now you must be quite bored with the updates because I am sure no one is going to build a project that is exactly same as mine. But in case you are following along, you might have picked up some things that you did not know earlier or may be you found somethings that you could have done differently. The reason I am writing is to keep a journal of things. While I fixed most of the issues with my setup, I still had a couple of problem that don’t happen frequently which makes it difficult to debug. In this post I will discuss the problems and my solutions. May be there are better solutions, but these are ones that I could come up with. A reader was lamenting that my posts are too short so I let this post go as long as it needs to be. So enjoy :).
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Solar Panel Project Update - Part 4
As I mentioned in my last post about solar panel setup, there still a few more issues with my sensors. One of them is temperature drift. When the weather is cool like early in the morning, the DC current sensors read one value and in the evening when the temperature is hot, they read a slightly different value. The difference is quite small but get magnified when doing the calculations. For example, in the night around 7 pm when there is no solar power, the sensor would read 2.5V which after all the transformations turns out to be 0 amps of current. All good. Then in the morning say around 5 am when there is still no sun, the sensor would read 2.52V. Not much of a difference, but it get magnified as I will soon show you.
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Solar Panel Project Update - Part 3
In my previous post I explained how I improved the accuracy of my DC sensors using ADS1115. But there is one problem though. The ADS1115 gives accurate reading even when the supply voltage keeps changing. Yet, the sensor values will not be correct. The reason is that if the supply voltage is changing, the reading on the sensor will also change, but the accuracy of the reading will be stable because ADS1115 is independent of power supply voltage fluctuations. For example, let’s say the supply voltage is 2.5V, then when there is no current, the DC current sensor will read 2.5V, and in the code we assume the current is 0 at 2.5V. Now if the supply voltage drops to 4V then the sensor will read 2V, which is still the mid point and indicates 0 current. But in the code we have a hard coded number that 2.5V is the midpoint and we mistakenly assume that some current proportional to -0.5V is passing through the wires. That is the problem.
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Solar Panel Project Update - Part 2
This is a continuation of my previous post giving updates about my solar panel setup. As you will probably remember from that post, I found a good sensor that would measure AC voltage and current accurately and I was satisfied and very confident about the data coming from the sensors. However, I cannot say the same about my DC measurements. Many components in the system should be measured in DC including solar panel current, battery voltage and current etc. My initial set of sensors were not accurate and used to drift quite a bit with supply voltage and ambient temperature. So I set out to find better sensors and upgraded them and I cover part of that story in this post.
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Solar Panel Project Update - Part 1
It has been a while since I gave any updates on my solar panel project so I thought I should write a post on it. This can get pretty technical so if you are not into electronics or software, you can skip. Since I last reported about my design I’ve made a few changes mainly to increase the stability of the system. What happened was that in the long run, I found some problems that rear their head sometimes intermittently. As a result I had to change the design to recover some components from their weird state. In addition I reduced the variability of readings by the sensors.
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